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Histamine in the blood
Medical expert of the article
Last reviewed: 04.07.2025
Reference values (norm) of histamine concentration: in whole blood - 180-900 nmol/l (20-100 μg/l); in blood plasma - 250-350 nmol/l (27.8-38.9 μg/l).
Histamine is found mainly in basophilic leukocytes and mast cells. In smaller quantities, it is found in the liver, kidneys, and intestinal cells. In the human body, histamine is formed during the decarboxylation of histidine. Histamine has a vasodilatory effect (reduces blood pressure), increases capillary permeability, causes contraction of the smooth muscles of the uterus, and stimulates the secretion of gastric juice rich in hydrochloric acid. In the blood, histamine is in a protein-bound form. Excess histamine in the blood quickly disappears during metabolism. The accumulation of histamine in the body can lead to pathological phenomena. Histamine is released from cells during anaphylactic and allergic reactions (immediate hypersensitivity mediator).
All types of allergic reactions are accompanied by an increase in the concentration of histamine, the degree of their severity is judged by the magnitude of the increase in the level of histamine. An increase in the concentration of histamine in the blood is also detected in carcinoids of the stomach and small intestine, mastocytoma, chronic myeloid leukemia, and true polycythemia.
Relationship between the magnitude of increase in histamine concentration in blood plasma and its biological effect
The magnitude of the increase in histamine, mcg/l |
Biological effect |
0-1 |
No |
1-2 |
Increased gastric secretion of HCL |
3-5 |
Tachycardia, skin reaction |
6-8 |
Lowering blood pressure |
7-12 |
Bronchospasm |
>100 |
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